Draw-bridge



(No Model.)

G. H. CRAFTS.

. DRAW BRIDGE. No. 433.828

Patented July 29, 18 90.

ATTORNEY.

UNITED STATES PATENT OFFICE.

GEORGE I-I. CRAFTS, OF ATIJANTA, GEORGIA.

DRAW-'BRIDG E.

SPECIFICATION forming part of Letters Patent No. 433,328, dated July 29, 1890.

To all rah-0111, it may concern:

Be it known that I, GEORGE II. CRAFTS, of Atlanta, in the county of Fulton and State of Georgia, have invented certain new and useful Improvements in Draw Bridges, of which the following is a full, clear, and exact description of the invention, such as will en able others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference, which form a part of this specification.

This invention relates to bridges, and more particularly to that class of bridges which are known as draw-bridges, the object of the invention being to provide a bridge of such construction that will be durable and at all times easy of operation. The construction whereby this end is attained is hereinafter fully described, and is shown in the drawings hereto annexed.

In the accompanying drawings, Figure 1 is a side elevation of the device, showing an iron bridge mounted on iron cylinder piers and stone abutments. Fig. 2 is a plan view of the device further illustrating the parts shown in Fig. 1. Fig. 3 isa section on the line a; a; of Fig. 2. Fig. 4 is a section 011 the line 3 y of Fig. 2.

In the figures, like reference marks indicating corresponding parts in the several views, A is the bridge, the trusses of which may be of any construction capable of standing the strains in a bridge of this character. The lower chord B of the truss is made of I-beams or beams of such construction as to form a rail with the tread on the under side, which tread bears on wheels, as will be hereinafter described.

On top of the pier O are the rollers D,which are suitably journaled thereon, and are as many in number as are equal to the proper sustaining of the center of the bridge under the load, and of any size desired. These rollers are preferably flanged in order to act as a guide for the rails B. The pier E, which is at the inner end of the draw-bridge, also carries rollers D and D, the rollers D being preferably on the shaft G, which carries the Application filed December 16, 1889. Serial No. 333,958- (No model.)

gear F, which engages with the pinion f, having crank f. On the shaft G are wheels H, being securely fastened thereon, over. which pass the cables or ropes I, of wire or other suitably strong material, which pass one or more times around the said wheels H and are secured to the crossbars a, while the other ends are secured to the cross-bar a, or in either case to some suitable part of the draw, their places of attachment being governed by the length of the withdrawal of the draw on the opening of the water-way. It is preferable that the wheels II be slightly concaved laterally in order that the ropes or cables may at all times remain near their centers.

If found necessary in very heavy draws, it would be preferable to increase the number of the cables and wheels H. The wheels H are about the same diameter as the rollers D on pier E, in order that there maybe no slipping of the contact between said rollers D and the chord B, and for this reason the said rollers will assist the cables in the moving of the draw. Any suitable landing-place may be provided for the outer end of the draw, one of which is shown in the accompanying drawings, and consists of a simple block on which the chord B may rest.

For the purpose of making the floor continuous a drop-section J is furnished, which may be raised 011 the opening of the bridge, and the draw be drawn onto the adjacent span by the revolution of the cable-drums in the direction of the arrow in Fig. 1.

The bracing of the trusses of this bridge will keep the chord B from sagging or being bent upwardly by the downward pressure of the bridge, and hence the bridge will be always free from objections due to the bending of the ways or rails on which it travels and is supported.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is-

In a bridge of the described class, the piers O and E, the rollers D, journaled in bearings mounted on the pier O, the shaft G, jonrnaled in bearings mounted on the pier E, the rollers D and H, keyed on said shaft, the gear-wheel F, attached to the outer end of said shaft and In testimony whereof I hereunto affix my meshing with the pinion f, journaled in suitsignature in presence of two Witnesses.

able supports, the rails B, carried by rollers D and D, the cables I, secured at their ends GEORGE H. CRAFTS. to the cross-bars a and a, respectively, said cable passing around the wheel H, and the Witnesses:

mechanism for operating the same, substan- A. P. WOOD,

tially as and for the purpose specified. S. M. WOOD. 

